Landing an aircraft is the most demanding task in flying. During the landing process, the aircraft must transition from operating in three dimensions of motion to operating in only two dimensions of motion and must be brought to a safe and complete stop. To perform the landing properly, the aircraft must approach the runway within certain attitude, track, speed, and rate of descent limits. An approach outside of these limits can result in the aircraft making a “hard” landing, overrunning the runway end, or otherwise contacting the runway surface in an uncontrolled manner. Any one of these events has the potential to cause severe damage to the aircraft and may additionally result in passenger injuries or fatalities.
In the past, a “too-low” approach was the most hazardous type of approach. However, the Ground Proximity Warning System/Enhanced Ground Proximity Warning System (GPWS/EGPWS) developed by Honeywell International, Inc. has reduced this risk significantly.
A “high energy” approach is now the highest risk, and a significant number of aircraft accidents and incidents are caused by high energy approaches. A high energy approach is an approach that is too fast and/or too high—that is, speed and/or altitude during the landing approach is excessive. The result of these “high energy” landing approaches may be a hard landing, over-running the runway, or departing the runway. For example, for each knot of airspeed in excess of a reference airspeed (unique to that aircraft and landing configuration on landing approach), the aircraft rollout distance may increase by approximately two percent. As a further example, aircraft approaching the runway at too steep an angle (that is, in excess of a nominal glidepath of around three degrees or so) have an excess amount of energy that must be dissipated during landing flare and touchdown. This condition not only places the aircraft at risk for undercarriage damage, but also may result in the aircraft floating down the runway during the flare in order to bleed off the excess energy. The runway distance consumed during the float is no longer available to stop the aircraft after touchdown and a runway overrun condition is possible.
Nonetheless, many successful landing approaches are made outside defined “stable approach” criteria. For example, successful approaches are made when air traffic control requirements cause conditions, such as a late turn to final approach or a late descent. Further, schedule pressure may cause conditions outside stable approach criteria, such as excessive airspeed.
As a result, it would be desirable to improve flight crew awareness of an impending problem with an approach—such as a high energy approach; to provide an advisory when probability of an unsuccessful approach is significant; to allow a margin from stable approach criteria; and to avoid increasing aural and visual clutter in the flight deck. However, there is an unmet need in the art for a system and method for monitoring and advising a flight crew of high energy landing approaches.